Abstract: Avalanche photodiodes and methods for forming them are disclosed. The breakdown voltage of an avalanche photodiode is controlled through the inclusion of a diffusion sink that is formed at the same time as the device region of the photodiode. The device region and diffusion sink are formed by diffusing a dopant into a semiconductor to form a p-n junction in the device region. The dopant is diffused through a first diffusion window to form the device region and a second diffusion window to form the diffusion sink. The depth of the p-n junction is based on an attribute of the second diffusion window.

Abstract: Avalanche photodiodes and methods for forming them are disclosed. The breakdown voltage of an avalanche photodiode is controlled through the inclusion of a diffusion sink that is formed at the same time as the device region of the photodiode. The device region and diffusion sink are formed by diffusing a dopant into a semiconductor to form a p-n junction in the device region. The dopant is diffused through a first diffusion window to form the device region and a second diffusion window to form the diffusion sink. The depth of the p-n junction is based on an attribute of the second diffusion window.

Abstract: An imaging sensor having sensitivity at the single-photon level is disclosed. The sensor comprises an array of pixels, each of which comprises a negative-feedback avalanche diode and a read-out circuit that includes a counter. The counter keeps track of the number of photons detected by the diode during a given time period.

Abstract: An imaging sensor having sensitivity at the single-photon level is disclosed. The sensor comprises an array of pixels, each of which comprises a negative-feedback avalanche diode and a read-out circuit that includes a counter. The counter keeps track of the number of photons detected by the diode during a given time period.

Abstract: A single-photon detector is disclosed that provides reduced afterpulsing without some of the disadvantages for doing so in the prior art. An embodiment of the present invention provides a stimulus pulse to the active area of an avalanche photodetector to stimulate charges that are trapped in energy trap states to detrap. In some embodiments of the present invention, the stimulus pulse is a thermal pulse.

Abstract: The present invention enables the detection of light using an APD that has high gain and/or a wide range of operating temperature. A first APD is biased with a voltage bias that is controlled based on the breakdown voltage of a second APD, which is thermally coupled with the first APD. Changes in the breakdown voltage of the second APD due to aging, temperature chances, and the like, are reflective of changes in the breakdown voltage of the first APD. As a result, the first APD can be operated with greater stability and reliability at high gain and over larger temperature excursions than APDs known in the prior art.

Abstract: A system for multispectral confocal mapping of a tissue, comprising: a light source; an optical fiber having an aperture providing a confocal pinhole, a scanner being free-space coupled to said aperture and operative to scan the tissue and provide intensity signals for each of a plurality of points therein; a switch or modulator operative to convert input signals to optical pulses; a reflector that receives the optical pulses and provides a temporal sequence of wavelength selective reflections; and, a detector optically coupled to receive the temporal sequence of wavelength selective reflections.

Abstract: Avalanche photodiodes are provided, wherein the APDs provide both high optical coupling efficiency and low dark count rate. The APDs are formed such that their cap layer has an active region of sufficient width to enable high optical coupling efficiency but the APD still exhibits a low dark count rate. These cap layers have a device area with an active region and an edge region, wherein the size of the active region is substantially matched to the mode-field diameter of an optical beam, and wherein the size of the edge region is made small so as to reduce the number of defects included. These APD designs maintain a substantially uniform gain and breakdown voltage, as necessary for practical use.

Abstract: A device for splitting light between the visible light spectrum and the near infrared light spectrum, particularly for separating reflected light between the visible light spectrum and the near infrared light spectrum, in determining multiple characteristics of product in a product scanning system. The invention also pertains to sorting machines that optically sort or separate nonstandard fungible objects from standard objects as they pass a viewing station by viewing such objects in at least two different wavelength spectrums and particularly to such sorting machines utilizing detector elements comprised of two or more different photo-sensitive devices and to the optical detection system used therein. The device includes a hermetically-sealed device with two transparent prisms between which is sandwiched indium tin oxide (ITO) selected to exhibit dielectric behavior in the VIS/NIR and metallic behavior in the NIR band.

Abstract: A single-photon avalanche detector is disclosed that is operable at wavelengths greater than 1000 nm and at operating speeds greater than 10 MHz. The single-photon avalanche detector comprises a thin-film resistor and avalanche photodiode that are monolithically integrated such that little or no additional capacitance is associated with the addition of the resistor.

Abstract: A single-photon avalanche detector is disclosed that is operable at wavelengths greater than 1000 nm and at operating speeds greater than 10 MHz. The single-photon avalanche detector comprises a thin-film resistor and avalanche photodiode that are monolithically integrated such that little or no additional capacitance is associated with the addition of the resistor.

Abstract: An imaging sensor for imaging scenes based on both shortwave infrared and midwave infrared radiation is disclosed. The imaging sensor comprises pixels that include a photodiode that is selectively sensitive to shortwave infrared radiation based upon its bias voltage.

Abstract: A single-photon detector is disclosed that provides reduced afterpulsing without some of the disadvantages for doing so in the prior art. An embodiment of the present invention provides a stimulus pulse to the active area of an avalanche photodetector to stimulate charges that are trapped in energy trap states to detrap. In some embodiments of the present invention, the stimulus pulse is a thermal pulse.

Abstract: An imaging sensor having sensitivity at the single-photon level is disclosed. The sensor comprises an array of pixels, each of which comprises a negative-feedback avalanche diode and a read-out circuit that includes a counter. The counter keeps track of the number of photons detected by the diode during a given time period.

Abstract: A single-photon detector is disclosed that provides reduced afterpulsing without some of the disadvantages for doing so in the prior art. An embodiment of the present invention provides a stimulus pulse to the active area of an avalanche photodetector to stimulate charges that are trapped in energy trap states to detrap. In some embodiments of the present invention, the stimulus pulse is a thermal pulse.

Abstract: A focal plane array suitable for use in hyperspectral imaging applications is provided. The focal plane array comprises pixels comprising arrays of photodiodes, wherein each photodiode in each array is selectively sensitive to a different wavelength of a set of wavelengths.

Abstract: Avalanche photodiodes are provided, wherein the APDs provide both high optical coupling efficiency and low dark count rate. The APDs are formed such that their cap layer has an active region of sufficient width to enable high optical coupling efficiency but the APD still exhibits a low dark count rate. These cap layers have a device area with an active region and an edge region, wherein the size of the active region is substantially matched to the mode-field diameter of an optical beam, and wherein the size of the edge region is made small so as to reduce the number of defects included. These APD designs maintain a substantially uniform gain and breakdown voltage, as necessary for practical use.

Abstract: Methods for fabricating an avalanche photodiode (APD), wherein the APD provides both high optical coupling efficiency and low dark count rate. The APD is formed such that it provides an active region of sufficient width to enable high optical coupling efficiency and a low dark count rate. Some APDs fabricated using these methods have a device area with an active region and an edge region, wherein the size of the active region is substantially matched to the mode-field diameter of an optical beam, and wherein the size of the edge region is substantially minimized and further wherein the device region maintains a substantially uniform gain and breakdown voltage.

Abstract: Avalanche photodiodes and methods for forming them are disclosed. The breakdown voltage of an avalanche photodiode is controlled through the inclusion of a diffusion sink that is formed at the same time as the device region of the photodiode. The device region and diffusion sink are formed by diffusing a dopant into a semiconductor to form a p-n junction in the device region. The dopant is diffused through a first diffusion window to form the device region and a second diffusion window to form the diffusion sink. The depth of the p-n junction is based on an attribute of the second diffusion window.

Abstract: A single-photon avalanche detector is disclosed that is operable at wavelengths greater than 1000 nm and at operating speeds greater than 10 MHz. The single-photon avalanche detector comprises a thin-film resistor and avalanche photodiode that are monolithically integrated such that little or no additional capacitance is associated with the addition of the resistor.